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"OS X can't repair disk"

Using a mid-2010 Power Mac with 4 internal hard drives (1T each) and 3 external hard drives and running OS X 10.12.6 (Sierra).

Recently had one of the internal drives go bad and spent days recovering information stored on the disk. Since it's clear the internal drive has physical flaws, I purchased an external 4T G-Drive to use in place of the internal drive. This means I now have FOUR external hard drives.

During the recovery process, whenever I rebooted, I noticed a message about one of my external hard drives that said "OS X can't repair the disk "External A." You can still copy files on the disk but you can't save changes to files on the disk. Back up the disk and reformat it as soon as you can.

I ignored this thinking it must be a mistake since that particular hard drive (External A) was not involved in the process on which I was working.

So, finally the restoration of information to the brand new external G-Drive ("External C") was completed.However, when I rebooted, this "OS X can't repair" message popped up for BOTH the External A and External C drives.

Upon checking each, I see the permissions are messed up. Both say that I can "only read" the drives.

Not sure how that happened. Is this an easy fix? Since the G-Drive is brand new, I can't imagine that it's failing so the message to 'back up and erase' makes no sense to me.

Thoughts?

Mac Pro (Mid 2010), macOS Sierra (10.12.6), 16 GB 1333 MHz DDR3

Posted on Nov 12, 2017 11:15 AM

23 replies

Nov 15, 2017 1:13 PM in response to Kappy

Kappy - I have plugged in and mounted each of the two external hard drives in question to another Mac in our household.

In both cases, when the drive mounted on the desktop, the "Mac OSX can't repair" window popped up; and upon checking "Get Info" it's clear that the permissions are not set up to allow user access.

Conclusion: It is not the external hard drives ... must be my system.

NOTE: When I started out, I was running El Capitan. As part of the "solution" to recover the bad internal HD, I was advised to upgrade to Sierra. Perhaps the permissions were changed before the upgrade and I just didn't notice?

At this point, I think I must contact Apple directly and talk with a senior advisor. I do appreciate all of the time and effort you've put into assisting me!

Kappy

Level 10

361,741 points

Nov 13, 2017 11:41 AM in response to KatieOConnell

Did you follow the instructions for booting into Single-user Mode? Did you execute the sudo su line?

Nov 12, 2017 4:13 PM in response to Kappy

Indeed, I have a Mac Pro. I stand corrected.

Thank you for your considered response. Had to be out this afternoon/evening but will do as you suggested first thing tomorrow.

Kappy

Level 10

361,741 points

Nov 13, 2017 11:45 AM in response to Kappy

Sorry, I missed the sudo line. My bad.

Nov 13, 2017 11:49 AM in response to Kappy

Yes, I was in single-user mode before rebooting and going into Terminal.

Nov 13, 2017 12:08 PM in response to Kappy

Started with CD / then sudo su and the rest of it ...

Still getting the "operation not permitted" on each command line

😢

Nov 13, 2017 12:22 PM in response to KatieOConnell

Additionally, I'm running Sierra rather than El Capitan ... would the instructions in the link you provided still work, do you think?

Nov 13, 2017 12:46 PM in response to Kappy

One clarification: When you say "try everything again from earlier" do you mean starting with the Terminal commands? Or should I reboot into Single user Mode and start with those commands?

"OS X can't repair disk"